Vertical axis turbine foils

ABSTRACT

Geometries of foil shapes that act particularly well to increase the power output of adjacent vertical axis turbines are presented.

This patent application claims the benefit of U. S. Provisional Patent Application No. 61/058235, Provisional 6-08: Improvements to renewable energy devices, filed Jun. 4, 2008, and 61/089,914, Provisional 8-08: FDDs and Turbines, filed Aug. 19, 2008.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to the use of foils with vertical axis turbines (VAWT). Although their main use is likely to be with wind, the inventions apply to any kind of fluid flow.

The author of this patent has previously patented the use of foils with VAWTs in application in PCT IL2007/000348, Flow Deflection Devices and Methods for Energy Capture Machines, filed Mar. 18, 2007. The current application adds new specifications of specific shapes and methods to the broad claims in the previous patent application.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 is a diagram of a convex foil on a VAWT.

FIG. 2 is a diagram of the geometric parameters of a VAWT with a foil.

FIG. 3 is a diagram of fluid flow in Case 15

FIG. 4 is a diagram of fluid flow in Case 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention presents velocity and energy enhancing additions in the vicinity of the blades of VAWTs.

Definitions: VAWT is an abbreviation for Vertical Axis Wind Turbine. It refers here to such a turbine in any flow of fluid. It may be this type even in a horizontal orientation. The term “fluid” refers to gas or liquid, and any reference to fluid refers to both unless otherwise stated. A WDD is a Wind Deflection Device and an FDD is a Flow Deflection Device; they are substantially synonymous with the terms “foil” or “airfoil” as all the above refer to aerodynamic objects that change the flow of a fluid. An FDD or WDD is a broader term because it may refer to partial outline foils that are incomplete. A foil is functionally adjacent to the turbine if it is effective in changing the power output.

The principles and operation of a VAWT foil according to the present invention may be better understood with reference to the drawings and the accompanying description.

Referring now to the drawings, FIG. 1 illustrates a VAWT with a stand and shaft (1) and the location of the turbine blades (2). A vertical axis turbine may be made with at least one foil set that is convex to the upstream flow of fluid into the turbine and superior or inferior to the turbine or both as per FIG. 1. A lower, convex foil is added in the vicinity of the blades. Said foil may or may not be connected to the turbine's body. The unique additional point is that the foil or foils (3, 5) are convex to the oncoming wind and located above and/or below the blades (2). If an upper foil is present, it may be supported by at least one pole (4). In one embodiment, a convex foil forms a ring around the shaft. In one embodiment this may be used for wind and in another for water.

FIG. 2 illustrates the model and parameters used for determining the foil shapes and gives a description of the major parameters. For the purpose of maintaining geometric ratios, Db is 1.96 meters, and Hb is 2 meters. Din (7) is the internal diameter of the foil (6 and/or 16). (8) is the chord of the foil at any angle. Note that it may refer to only part of the foil structure. The blades are (9). Sb (10) represents the distance from the foil to the blade. In all models shown below, S_(b)=2.5cm. Hb (11) is the height of the blades. Cb (12) is the chord of the blades. Db (13) is the diameter of the blades. H1 (14) is the height of the outer vertical flange (leading edge according to the wind direction) extending from the more traditional foil shape (6 and 16). In one embodiment of a vertical axis turbine surrounded by a partial outline foil described in previous patents, a substantially vertical flange facing the outside and inferior to the outer edge can be added to increase the velocity of fluid entering the turbine. H2 (15) is the height of the inner flange (trailing edge according to the wind direction) attached to the partial outline foil. In the models below, the chord is c and it is at an angle of α.

It is emphasized that the deflection “foils” here can contain up to three parts: an outer flange, an intermediate foil, and an inner flange.

The models here use a C foil as the intermediate foil shape. The body of the foil is a “C” foil, which was illustrated in a previous patent as a line drawn through the following relative coordinate points in an x-y axis in any proportional size and any angle of attack, wherein at least one point can vary by an absolute amount of 10% of the chord length: X, Y; 1.732050808, 1; 1.693643087, 0.874364124; 1.646368289, 0.761206475; 1.542617362, 0.546668353; 1.427110653, 0.347651841; 1.29972529, 0.165009761; 1.159575723, 0.000955932; 1.004940323, −0.140607698; 0.824000258, −0.251170312; 0.72335477, −0.288447214; 0.614950141, −0.310804889; 0.497740627, −0.315152056; 0.369386895, −0.29535687; 0.299593086, −0.272790447; 0.224224918, −0.23736895; 0.1390843, −0.179461075; 0.088459869, −0.132016988; 0, 0. It is now presented here in association with a vertical axis turbine. In the use of a partial outline C foil with internal and/or external flanges used with a vertical axis turbine, the following proportional arrangements are claimed, within a margin of error of 10% of the chord length of the points in either the x or y axis. The inner diameter of the WDD is D_(in), the chord is c and it is at an angle of α, and flange sizes, H₁ & H₂. The body may be composed of foil structures other than a C foil in other embodiments; C is just the ideal. The cases solved and an estimation of the Available Wind Power Increase (AWPI) (%) are in the following table.

Case c (m) D_(in) (m) α (°) H₁ (cm) H₂ (cm) AWPI (%) 1 0.375 1.73 26 7 11 25 2 0.5 1.50 26 7 11 48 3 0.625 1.28 26 7 11 53 4 0.75 1.05 26 7 11 42 6 0.5 1.50 26 14 11 53 7 0.5 1.50 26 21 11 38 8 0.5 1.50 26 7 22 52 9 0.5 1.50 26 14 22 46 10 0.5 1.36 40 7 11 23 11 0.5 1.44 33 7 11 27 12 0.5 1.55 20 7 11 67 13 0.5 1.58 14 7 11 62 14 0.5 1.55 20 7 22 58 16 0.5 1.55 20 0 0 58

We claim the proportions of c, Din, angle of attack, and flange sizes as shown, wherein the outside diameter is approximately 2.40-2.50 meters, with a margin of 10% of the value of chord length, Din, or angle of attack, in any proportional size. The H1 or H2 parameters can vary by a margin of 10% of the chord of the foil. We claim the proportion of a Din of 1.4 meters or greater in relation to a chord length of .4 to .6 meters or an angle of attack of 5 degrees or greater. We claim the proportion of Din/Dout of 1.0-1.8 meters to 2.40-2.50 meters, within a margin of 10% as being an ideal embodiment for the ratio for empty internal space to foil outer diameter for a vertical axis turbine with a foil shape in the orientation presented here.

We introduce the use of a partial outline foil shape in conjunction with a flange on any single side or at least two sides for use in combination with a turbine, in one embodiment in gas, in another embodiment in liquid, in another embodiment in a vertical axis turbine, in another embodiment as a shroud for a horizontal axis turbine. This may be with or without an internal and external flange, or both.

We present the criterion for design of the foil above and/or below a VAWT that there should not be vortices in the internal area between the upstream and downstream sections of the foils. In FIG. 3, which illustrates the wind flow by arrows in case 15, a low-power geometry, (17) represents the upstream foil and (18) the downstream area on the opposite side of a ringed foil shape. The highest part of the bar represents the greatest amount of velocity and percentage increase in power output. (19) in the center shows areas of vortices. FIG. 4, in contrast, illustrates Case 12, with (20) being the upstream area and (21) the downstream area. Area (22) in the center illustrates a lack of vortices because there is sufficient space to channel the fluid out of the enclosure without vortices. The geometry of case 15 is as follows:

Case c (m) D_(in) (m) α (°) H₁ (cm) H₂ (cm) AWPI (%) 15* 1.04 0.53 26 0 0 9

While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.

SUMMARY OF THE INVENTION

The present invention successfully addresses the shortcomings of the presently known configurations by providing a series of optimal foil/vertical axis turbine configurations.

According to another embodiment,

It is now disclosed for the first time a vertical axis turbine, comprising:

a. a functionally adjacent, externally convex FDD upstream from the turbine.

According to another embodiment, the FDD is inferior (as per the orientation to the base of the turbine, no matter what direction the turbine faces, base defined as the point of connection to the energy output) to the turbine's blades.

According to another embodiment, the FDD is superior to the turbine's blades.

According to another embodiment, the FDD is inferior and superior to the turbine's blades.

According to another embodiment, the FDD is not connected to the body of the turbine.

According to another embodiment, the FDD forms a ring around the shaft.

According to another embodiment, the turbine is in a liquid.

It is now disclosed for the first time an FDD for a turbine, comprising:

a. an intermediate partial outline foil shape, wherein the foil is adjacent to the turbine blades by a distance of less than 10% of the foil's outer diameter. b. a substantially vertical flange at the end of the foil shape on one side.

In one embodiment, the system further comprises

c. a substantially vertical flange at the end of the foil shape on the second side.

According to another embodiment, the FDD is functionally adjacent to a vertical axis turbine.

According to another embodiment, the FDD is functionally adjacent to a vertical axis turbine.

According to another embodiment, the intermediate shape is a “C” foil.

It is now disclosed for the first time a vertical axis turbine, comprising:

a) proportional parameters of Db 1.96 meters, and Hb 1.5-3 meters within a 10% margin of their values. b) at least one functionally adjacent FDD in a vertical orientation.

In one embodiment, the system further comprises additional parameters of the FDD according to cases in the following table, with a margin of error of 10% of the value of chord length, Din, or angle of attack, in any proportional size, or of the H1 or H2 parameters by a margin of 10% of the chord of the foil in any proportional size, for any one, two, three, four, or five of the parameters in the columns below:

Case c (m) D_(in) (m) α (°) H₁ (cm) H₂ (cm) 1 0.375 1.73 26 7 11 2 0.5 1.50 26 7 11 3 0.625 1.28 26 7 11 4 0.75 1.05 26 7 11 6 0.5 1.50 26 14 11 7 0.5 1.50 26 21 11 8 0.5 1.50 26 7 22 9 0.5 1.50 26 14 22 10 0.5 1.36 40 7 11 11 0.5 1.44 33 7 11 12 0.5 1.55 20 7 11 13 0.5 1.58 14 7 11 14 0.5 1.55 20 7 22 16 0.5 1.55 20 0 0

It is now disclosed for the first time a vertical axis turbine, comprising: an inferior or superior FDD, with the proportion of a Din of 1.0-1.8 meters or greater in relation to a chord length of .4 to .9 meters, with an angle of attack of 5 degrees or greater.

It is now disclosed for the first time a vertical axis turbine with an inferior or superior FDD, comprising: the proportion of Din/Dout of 1.0-1.8 meters to 2.30-2.60 meters.

It is now disclosed for the first time a vertical axis turbine, comprising an FDD, wherein fluid vortices as determined by fluid dynamic analysis and/or testing are not present from passage of fluid without blades in the internal diameter of the FDD from the bottom to the top of the FDD.

It is now disclosed for the first time a method of apposing an FDD to the blades of a vertical axis turbine, wherein the internal area of the FDD produces only non-vortical flow. 

1. A vertical axis turbine, comprising: a. a functionally adjacent, externally convex FDD upstream from the turbine and not interposing between the fluid flow and the blades and attached to said turbine.
 2. The turbine of claim 1, wherein the FDD is inferior (as per the orientation to the base of the turbine, no matter what direction the turbine faces, base defined as the point of connection to the energy output) to the turbine's blades.
 3. The turbine of claim 1, wherein the FDD is superior to the turbine's blades.
 4. The turbine of claim 1, wherein the FDD is inferior and superior to the turbine's blades.
 5. The turbine of claim 1, wherein the FDD is not connected to the body of the turbine.
 6. The turbine of claim 1, wherein the FDD forms a ring around the shaft.
 7. The turbine of claim 1, wherein the turbine is in a liquid.
 8. An externally convex FDD, not interposing between the fluid flow and the blades and attached to a turbine, comprising: a. an intermediate partial outline foil shape, wherein the foil is adjacent to the turbine blades by a distance of less than 10% of the foil's outer diameter. b. a substantially vertical flange at the end of the foil shape on one side.
 9. The FDD of claim 8, further comprising: c. a substantially vertical flange at the end of the foil shape on the second side,
 10. The FDD of claim 8, wherein the FDD is functionally adjacent to a vertical axis turbine.
 11. The FDD of claim 9, wherein the FDD is functionally adjacent to a vertical axis turbine.
 12. The FDD of claim 8, wherein the intermediate shape is a “C”.
 13. A vertical axis turbine, comprising: a) proportional parameters of Db 1.96 meters, and Hb 1.5-3 meters within a 10% margin of their values. b) at least one functionally adjacent externally convex FDD, not interposing between the fluid flow and the blades and attached to said turbine, in a vertical orientation.
 14. The turbine of claim 13, further comprising additional parameters of the FDD according to cases in the following table, with a margin of error of 10% of the value of chord length, Din, or angle of attack, in any proportional size, or of the H1 or H2 parameters by a margin of 10% of the chord of the foil in any proportional size, for any one, two, three, four, or five of the parameters in the columns below: Case c (m) D_(in) (m) α (°) H₁ (cm) H₂ (cm) 1 0.375 1.73 26 7 11 2 0.5 1.50 26 7 11 3 0.625 1.28 26 7 11 4 0.75 1.05 26 7 11 6 0.5 1.50 26 14 11 7 0.5 1.50 26 21 11 8 0.5 1.50 26 7 22 9 0.5 1.50 26 14 22 10 0.5 1.36 40 7 11 11 0.5 1.44 33 7 11 12 0.5 1.55 20 7 11 13 0.5 1.58 14 7 11 14 0.5 1.55 20 7 22 16 0.5 1.55 20 0 0


15. A vertical axis turbine, comprising: an inferior or superior externally convex FDD, not interposing between the fluid flow and the blades and attached to said turbine, with the proportion of a Din of 1.0-1.8 meters or greater in relation to a chord length of .4 to .9 meters, with an angle of attack of 5 degrees or greater.
 16. A vertical axis turbine with an inferior or superior externally convex FDD, not interposing between the fluid flow and the blades and attached to said turbine, comprising: the proportion of Din/Dout of 1.0-1.8 meters to 2.30-2.60 meters.
 17. A vertical axis turbine, comprising an FDD, wherein fluid vortices as determined by fluid dynamic analysis and/or testing are not present from passage of fluid without blades in the internal diameter of the FDD from the bottom to the top of the FDD.
 18. A method of apposing an FDD to the blades of a vertical axis turbine, wherein the internal area of the FDD produces only non-vortical flow. 